MICROSTRUCTURE OF MECHANICAL ALLOYED SI76GE23.95P0.05

Mechanical alloying of pure Silicon and pure Germanium powders and sma ll P-amount leads to an alloy which contains grains with a size of abo ut 10nm. The grain size and the progress in formation of the Si76Ge23. 95P0.05 alloy depends strongly on the milling time and the subsequent hot isostatic pressing. The microstructure was characterized by x-ray diffractometry (XRD) and TEM-observations. Most of the nanocrystalline grains ale sintered to particels with a size of 100 mu m. Using Energ y Dispersive Spectrometry (EDS) the diffusion concentration profile wi thin the larger grains could be measured. After a milling time of 250h the Si to Ce ratio has reached a constant value. The process of homog enization can be sucessfully described using a model based on the supe rposition of the different diffusion processes. The material has a gre at perspective for thermoelectric purposes.